The present invention relates to data storage systems, and relates more particularly to a system and method for providing a virtual volume data storage in a user site.
Managing a large data storage system is very difficult. Typically, a data storage service provider provides a storage-related service such as providing storage volumes, data backup, and the like. From a user site, if a user connects to this storage via the storage service provider""s directory, then the user must use a long distance connection to connect to this storage. This process causes more delays than if a user is connecting to a local storage.
The World Wide Web (WWW) effectively acts as a storage system in a wide area. The user may deploy a proxy server in the user site. As known to those skilled in the art, a proxy server is a server that sits between a client application (such as a web browser) and a remote server. The proxy server provides a cache of items that are available on the remote servers. The proxy server intercepts all requests that are made to the remote server so that the proxy server can determine if it can instead fulfill the request. If the proxy server is unable to fulfill the request, then the proxy server will forward the request to the remote server for processing. A proxy server can just only read cache data from the remote server or site, and it does not support a write procedure to the remote server or site. Additionally, the proxy server can not provide a service that depends on the data feature. As a result, the proxy server causes an ineffective usage of resources, and the use of a proxy server also causes more delays than the use of a local storage.
U.S. Pat. No. 5,155,835 discloses a multilevel, hierarchical, dynamically mapped data storage subsystem. This patent reference does not disclose storage systems between wide area networks (WANs) and ignores data features such as access interface type (block or file, and the like), purpose (user data or system file or backup file and the like). Thus, the subsystem disclosed in this reference is inefficient.
The Internet protocol small computer system interface (iSCSI) uses the Internet Protocol (IP) networking infrastructure to quickly transport large amounts of block storage (SCSI) data over existing local area and/or wide area networks. With the potential to support all major networking protocols, iSCSI (IP SAN) can unify network architecture across an entire enterprise, thereby reducing the overall network cost and complexity. To ensure reliability, iSCSI can use known network management tools and utilities that have been developed for IP networks. The iSCSI protocol is discussed, for example, at the website, http://www.ece.cmu.edu/xcx9cips/index.html) in the IP Storage section, http://www.ece.cmu.edu/xcx9cips/Docs/docs.html.
The working group of Internet Engineering Task Force (IETF) at http://www.ietf.org provides a network file system (NFS) version 3 (rfc1813 of IETF) and a common Internet File system (CIFS) protocol (http://www.cifs.org).
The NFS is an open operating system that allows all network users to access shared files that are stored in different types of computers. NFS provides access to shared files through an interface called Virtual File System (VFS) which runs on top of the Transmission Control Protocol/Internet Protocol (TCP/IP). With NFS, computers connected to a network can operate as clients while accessing remote files and as servers while providing remote users access to local shared files.
The CIFS protocol defines a standard for remote file access using millions of computers at a time. With CIFS, users with different platforms and computers can share files without having to install new software. CIFS runs over TCP/IP, but uses the Server Message Block (SMB) protocol found in Microsoft Windows for file and printer access. Therefore, CIFS will allow all applications (including Web browsers) to open and share files across the Internet.
The websites http://www.cnt.com and http://www.san.com describe wide area network (WAN) connections to a storage or storage area networks (SANs). The WAN connection may be an asynchronous transfer mode (ATM), synchronous optical network SONET), and the like.
The above references do not disclose methods for providing hierarchical management techniques between storage systems and host devices.
There is a need for a system and method that will overcome the above-mentioned deficiencies of conventional methods and systems. There is also a need for a system and method that will permit an access service provider to have a reliable storage system and that will permit a user to quickly access the storage system. There is also a need for a system and method that will permit an access service provider to be able to tune a local storage system based upon user statistic data and user log data.
The present invention may advantageously provide a reliable virtual local storage in a user site. The present invention may also advantageously provide a virtual local storage that permits faster access for a user. The present invention may also advantageously permit a service provider to tune up the local storage by using user statistics data and user log data that are tracked by the local storage, and the service provider may then charge the user for these tuning services.
In one embodiment, the present invention permits a service provider to provide a data storage service via a wide area network. A virtual volume storage is deployed at the user site. The virtual volume storage allows a host(s) at the user site to access the service provider storage located at the service provider site. The virtual volume storage advantageously permits the user to avoid having to access each time the wide area network coupled between the user site and the service provider site.
In one embodiment, the present invention broadly provides a system for providing a data storage service, comprising: a service provider site configured to provide a data storage service; and a user site coupled by a wide area network (WAN) to the service provider site, the user site comprising a local storage having a virtual storage, the virtual storage having a synchronous volume and an asynchronous volume, the local storage configured to immediately transmit to the service provider site data that is written in the synchronous volume, to transmit at a predetermined schedule to the service provider site data that is written in the asynchronous volume, and to read data from the service provider site if the data is not stored in the local storage.
In another embodiment, the present invention provides a method of managing data in a local storage based on the data feature. The virtual volume storage in the local storage determines if the data is static or cached, and synchronous or asynchronous. The virtual volume storage can also manage data not only by storage volume, but also by directory, file, cylinder, and/or block address.
In another embodiment, the present invention provides a method of tracing the access activities of a user in the user site. The user access activities are recorded to permit the service provider to analyze patterns in the user access activities. Based on this analysis, the service provider can tune the virtual volume storage in the user site.